(2,4-dichlorophenoxy) acetic acid

(2,4-di·chlor·o·phen·ox·y) a·ce·tic ac·id (2,4-D),

(dē-klōr'ō-fe-nok'sē a-sē'tik as'id),
An herbicide, more toxic to broad-leaved dicotyledonous plants (weeds) than to monocotyledonous ones (grains and grass), used with (2,4,5-trichlorophenoxy)acetic acid as a constituent of Agent Orange.